Genesis 24:2-4

He said to the senior servant in his household, the one in charge of all that he had, “Put your hand under my thigh. I want you to swear by the LORD, the God of heaven and the God of earth, that you will not get a wife for my son from the daughters of the Canaanites, among whom I am living, but will go to my country and my own relatives and get a wife for my son Isaac.”